Treatment of heavy hydrocarbons



A. FISHER TREATMENT OF HEAVY HYDROCARBONS June 6, 1933.

Filed D90. 28, 1931 INVENTOR ALFRED FISHER *%M%/% ATTORNE Patented June6, 1933 UNITED STATES PATENT OFFICE mm FISHER, O! CHICAGO, ILLINOIS,ABSIGHOB TO UNIVERSAL OIL PRODUCTS GOI- PLNY, OI CHICAGO, ILLINOIS, AOORPORATION 0] SOUTH DAKOTA.

rmmnr OI HEAVY HYDROGABBONS Application fled December 88, 1981. SerialIto. 583,001.

This invention relates to the treatment of solid carbonaceous andhydrocarbon oil mixtures and more particularly refers to substantialdevolatilization or coking of materials such as hydrocarbon oilscontaining coal, petroleum coke or the like in finely dis ersed form.

he use of externally heated rotary retorts for continuously cokingmixtures of' oil and carbonaceous material has been previouslydisclosed. The present invention 1s concerned with improvements toprocesses and apparatus of this type, the primary.

princi les of which comprise intermittently arresting the cokingoperation, perm1tt1ng the retort to coolsomewhat and causing the layerof coke or carbonaceous material to break and scale away from the wallof the retort, due to their unequal contraction so that it may beremoved from the zone of treatment. After the cooling and coke-removingperiod the coking operation may continue as before.

I have found that by this method of removing coke which ad eres to thewalls of the retort it normally falls away in relatively large piecesthus minimizing the iproduction of small coke particles or nes whichpredominate in many other methods of coke removal. This feature obviatesthe necessity of briquetting the carbonaceous fuel. It is alsocharacteristic of the process of the present invention that thetemperature in the coking zone may be reduced only sufficiently to causethe adhering carbonaceous la er to crack and scale away from the walls 0the retort, after which the coking operation may be resumed withoutfirst substantially increasing the temperature of the heated retoreshell. This is due to the fact that the furnace temperature preferablyis gradually increased as the layer of carbonaceous material builds u onthe walls of the retort, to com ensate or the reduced rate of heat transer caused by the insulating properties of said carbonaceous material,resulting in a substantially higher temperature in the retort shell atthe end than at the start of the coking period. Thus the tem perature towhich-the retort shell is cooled during the cleanin period may not besubstantlally lower t an the temperature required to start thesucceeding coking operathe process of the present invention may beaccomplished. The drawing and the following description are given forthe purpose of more clearly illustrating the novelty and features of theinvention. The rotar retort is indicated in general at 1. Thecylindrical shell 2 of the retort is located in a suitable furnacesetting 3 and is rotated by any suitable motivating means, not shown,throu h gear arrangement 4. Ends 5 and 6 of t e retort, located outsidethe heating zone of the furnace, preferably are stationary and anysuitable orm of packing arrangement, not shown, isprovided between therotary shell 2 and stationary ends 5 and 6 to prevent escape ofmaterials from the retort.

Any suitable fuel such as oil, gas, pulverized solid fuel or the like issupplied to combustion zone 7 of the furnace by means of any suitableburner, not shown, through burner port 8. The hot combustion gases passupward through the perforated arch 9 of the furnace, along shell 2 ofthe retort through heating zone 10 and out of the furnace to a suitablestack, not shown, through flue opening 11.

p The material to be coked may be supplied to the retort through line 12and valve 13 falling upon a heated portion of shell 2 in a relativelythin stream from nozzle 14, it being understood that where coal or othersolid matter is treated alone that the inlet feed pipe should besuitable for such .purpose. Rotation of the retort shell 2 and slightinclination of the retort from the horizontal toward its discharge andeffects substantially uniform distribution of the material suppliedthereto over the entire inner surface of shell 2. Rotation of the retortalso assists in maintaining a substantially uniform temperature aroundthe entire circumference of the shell and the material distributed' overthe walls of the shell is substantially devolatilized and reduced tocoke or carbonaceous residue.

As a la er of coke or carbonaceous material buil up upon the innersurface of shell 2, the poor heat conductivity of the carbonaceousmaterial will reduce the flow of heat from the furnace to the materialundergoing coking. To offset this reduction in the rate of heat transferthe furnace temperature preferably is gradually increased durin thecoking operatlon. The heated shell 2 o the retort is preferablyconstructed of a suitable metallic alloy, such as nickel chromium steel,capable of withstanding the relatively high temperatures to which theshell of the retort is sub'ected.

After a substantial layer of coke as been built up upon the innersurface of revolving shell 2 of the retort the supply of charging stockto the zone of treatment is stoppe Preferably heating of the retort iscontinued for a time after the feed is discontinued to substantiallyvaporize any volatile matter remaining on the surface of the coke layer.Firing is then discontinued to allow the retort to cool, thusestablishing unequal contraction between the metal shell and thecarbonaceous layer, the shearing force of which causes the layer ofcarbonaceous material to break and scale away in relatively largepieces. The slight inclination and the rotation of the retort causes thedislodged carbonaceous material to pass to the discharge end 6 of theretort from which it is removed throu h coke discharge tube 18.

Either or both of the stationary ends 5 and 6 of the retort may beprovided with removable plugs 16. B means of openings 17, provided withthe .p ugs 16 are removed, a rod, not shown, preferabl sharpened at itsend may be inserted and orced by means of a hydraulic ram, compressedairn or other suitable means, not illustrate into the carbonaceous massat a point close to the inner surface of shell 2, thus starting orassisting the breaking and scaling away of the coke during the coolingand cleaning period. Rotation of the retort is, of course, stoppedduring the rodding operation and a jet of steam may be directed throughthe openin 17 to prevent the escape of hot gases rom the retort.

The lower. end of coke discharge tube 18 is preferably immersed inliquid which acts as a seal to prevent the escape of vapors and gasesthrough this port. Any suitable liquid such as oil or water may beemployed and may serve also as a quenching medium for the coke. Coke maybe discharged during the intermittent cleaning operation of the retortonto a continuous conve or 19 of an suitable form, one end of which isimmerse in the liquid seal and qluenching chamber 20' and b means ofwhic the coke may be resired. Coking temperatures emp A line 12'controlled by valve 18' is provided for introduc' steam or water intothe retort, when desirable, to assist cooling of the retort during thecoke-removing period and/ or to keep t e oil inlet nozzle 14 free ofobstructions.

Va ors removed from the retort through line 1 and valve 22 ma pass tofractionation, condensation, coo ing and collection apparatus or to anyother apparatus for des1red treatment, means for which are well knownand are not shown on the drawing. If desired, the heavy portions of theva ors may be separated from the li hter portions by fractionation andreturn to the retort for further treatment together with the charginstock, b well known means not illustrate in the rawing.

Preferably the process is operated at substantially atmospheric pressurealthough relatively low super-atmospheric pressures or partial vacuummay be employed, if deoyed may range from 900 to 1300 F., more or less,de-

nding primarily u on the type of material eing treated and t e desiredvolatility of the coke produced as well as the desired characteristicsof the other products of the process. Preferably the temperature of theretort is reduced by from 300 to 600 F.,

more or less, during the cooling and cokeremoving period of theoperation.

As a specific example of the operation of the process of the presentinvention, a heavy fuel oil and about 200 mesh coal admixed insubstantially equal parts by weight is supplied to the externally heatedrotary retort at the rate of about 1000 pounds per hour. The furnacetemperature, i. e., the tem erature measured in the heating zone 0 thefurnace adjacent to but outside of the rotary shell of the retort, isabout 1350 F. when the feed is started. This temperature is increased,for example, by injecting a reater amount of fuel into the furnace, at te rate of about 100 F. per hour to approximately 1650 F. Thistemperature is maintained for about 7 hours during which time the rateof feed is gradually decreased to approximately 350 pounds per hour. Thesupply of carbonizable material being fed is then stopped and thefurnace temperature is increased from approximately 1650 to about 1750F. after which the fires are extinguished, permitting the retort to coolover a period of ap roximately one hour to about 1400 F. at which timesubstantially all of the carbonaceous material will have been dislodgedfrom the walls of the retort and discharged from the zone of treatment.Durin the coking operation the vapors and gases rom the retort aresubjected to fractionation, their relatively heavy components comprisingabout 30 percent of the total move to storage or elsewhere, as desired.liquid produced, being recycled to the retort for further treatment,together with the charging stock, while the remainder of the distillateis subjected to condensation and cooling and separated from the gas.

.An operation such as above outlined may yield approximately 50 percent,based on the weight of the charging stock, of coke, the maximum of whichis recovered in relatively large pieces. This material may have avolatile content of about 8 percent and is suitable for domestic fuel aswell as many other purposes. About 22 percent by weight of gas, having acalorific value of approximately 950 B. t. us percubic foot may also berecovered and in addition a total liquid recovery of approximatelypercent by weight, some 6 to 8 percent of which may comprise motor fuelhaving an antiknock value equivalent to an octane number of 85 or more,may be recovered. The liquid products among other uses are highlysuitable ascharging stock for cracking.

I claim as m v invention: 1. A process or the treatment of carbonizablematerials to produce. coke and cracked liquid products which comprisesintroducing the carbonizable material in a continuous stream into arotati g retort, simulta neousl heating the rotating shell of the retortw ereby the material introduced there to adheres to the inner surfacethereof and is reduced to coke, causing the coke to build up upon theheated walls of the retort and simultaneously increasing the fur- 2. Aprocess for the treatment of hydroearbon oil and coal mixtures toproduce coke and cracked liquid products which comprises introducing themixture in a continuous stream into a rotating retort, simultaneouslheating the rotating shell of the rewhereby t e material introducedthereto adheres to the inner-surface thereof and is reduced to'coke,causingthe coke to build upu' on the'heatedmalls of the retort and mmtaneously increasing thefurnac'e temperature around the retort tocompensate or the decreased rate of heating and cokionf caused "by theinsulating'coke layer, peri ically stoppingthe .supply of coal and oilmixture to the retort and s' ultaneously discontinuing heating of theretprt,.so as to allow it to cool to apredetermined temperature wherebythe dc osited coke is loosened from the retort w removin the cokefrom-the retort, then resuming eating of the. retort and again admittingthe coal andoil mixture thereto to repeat the operation above described.

r 3. A process for the treatment of heavy A hydrocarbon oils to producepetroleum coke and cracked liquid products which comprisesintroducingthe oil in a continuous stream into a rotating retort, simultaneouslyheating the rotating shell of the retort whereby the material introducedthereto adheres to the inner surface thereof and is reduced to coke,causing the coke to build up u on the heated walls ofthe retort and simutaneously increasing the furnace temperature around the retort tocompensate for the decreased rate of heating and coking causedby theinsulating coke layer, periodically stoppin the supplfisof oil to theretort and sim taneously continuing heat-- ing of the retort, so as toallow it to cool to a predetermined temperature whereby the depositedcoke is loosened from the retort walls, removing the coke from theretort,

then resuming heating of the retort and again admitting the heavyhydrocarbon oil thereto -to repeat the operation above described.

4. A process, as defined in claim 1, wherein steam is admitted duringthe cooling and coke-removing period.

5. A process for the treatment of carbonizable materials to produce cokeand cracked liquid products which comprises externally heating arotatable retort to a predetermined temperature and introducing thecarbonizable material in a continuous. stream into the rotating retort,causing said materials to spread over the inner surface of the retort inrelatively thin layers, externally heating the rotating retort to reducethe material introduced lnto the retort to coke, whereb the coke buildsupon the heated inner sur ace of the retort, regulating the temperaturearound the retort to increase the temperature thereof to compensate forthe decreased rate of heat transference through the built upheatinsulating coke, decreasing the rate of supply of carbonizablematerial to said retort as the layer of coke increases, periodicallystoppin the supply of carbonizable material to t e retort, andconcurrently stplpping the heating OfthBIGfOI'tSOBStD OWIlZtOOOOIUObelow the first mentioned predetermined temperature, whereby thedeposited coke is loosened from the retort walls, removing the coke fromthe retort, then resuming heating of the retort and againadmittinicarbonizable material thereto to repeat t e operation abovedescribed.

In testimony whereof I afiix mly s1 ature.

ALFRED IS B.

